In engineering, thin-walled cylindrical shells subjected to axial compression load are very sensitive to geometric imperfections and are prone to buckling. However, how to reasonably take into account the influence of geometric imperfections on the load carrying capacity of thin-walled cylindrical shells is always the bottleneck of light-weight design of these structures. In this paper, four perturbation load approach (4PLA) is adopted to consider the influence of geometric imperfections. By judging the potential buckling status of cylindrical shells, a new improved design method based on 4PLA for thin-walled cylindrical shells is proposed, in which the influence of radius-to-thickness ratio, length-to-radius ratio, Young’s modulus and material yield strength are systematically considered. Correspondingly, the buckling tests for two steel cylindrical shells with the same geometric and material parameters are conducted. Compared with the experimental results and other test results in open literatures, the superiority and safety of proposed method for the preliminary design of thin-walled cylindrical shells are validated.